Basic Bridge Types
Rolling Lift Bridge, Cermak Road Bridge, 1959
Engineer William Scherzer developed a rolling lift bridge that had two leaves that rolled back onto each bank. This bridge was inexpensive and easy to maintain, but weaknesses emerged over time. The Cermak Road Bridge is one of the remaining bridges of this type at 500 West Cermak.
See also: Bridges; Chicago River; Near South Side
Trunnion Bascule Bridge, Cortland Avenue, 1953
The first trunnion bascule bridge was built in Chicago at Cortland Avenue in 1902. This is the bridge type for which Chicago engineers are perhaps most famous. The trunnion bascule has one or two bridge leaves hinged on opposing riverbanks. The bridge is drawn up by giant trunnion bearings. Bascule is French for "seesaw"; the bridge is named for the counterweights that balance the great weight of the bridge leaves. Each of these bridges must be built for a specific location so no two are exactly alike. This is an aerial shot of the Cortland Street Bridge looking north in 1953.
See also: Bridges; Near North Side
Trunnion Bascule Bridge, LaSalle Street, 1928
The LaSalle Street Bridge, seen here just prior to completion in 1928, was built across the main stem of the Chicago River. This photograph provides an excellent view of the "Chicago style" trunnion bascule bridge, with its gentle curves and steel frame. It contrasts with the swing bridge still visible to the west at Clark Street, which was the last remaining swing bridge on the Main Branch of the Chicago River (built in 1888). The current Clark Street Bridge, a trunnion bascule, was completed in 1929. Newly completed Wacker Drive is seen on the right of the photograph.
See also: Chicago River; Bridges
Trunnion Bascule Bridge, Columbus Drive, 1982
The second-longest bascule bridge in the world was completed at Columbus Drive over the main stem of the Chicago River in 1982. The bridge is 269 feet long and cost $33 million.
See also: Bridges; Chicago River
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